src/mem/bus.hh

   1 /*
   2  * Copyright (c) 2002-2005 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Ron Dreslinski
  29  *          Ali Saidi
  30  */
  31
  32 /**
  33  * @file
  34  * Declaration of a bus object.
  35  */
  36
  37 #ifndef __MEM_BUS_HH__
  38 #define __MEM_BUS_HH__
  39
  40 #include <string>
  41 #include <list>
  42 #include <inttypes.h>
  43
  44 #include "base/range.hh"
  45 #include "mem/mem_object.hh"
  46 #include "mem/packet.hh"
  47 #include "mem/port.hh"
  48 #include "mem/request.hh"
  49
  50 class Bus : public MemObject
  51 {
  52     /** a globally unique id for this bus. */
  53     int busId;
  54
  55     static const int defaultId = -1;
  56
  57     struct DevMap {
  58         int portId;
  59         Range<Addr> range;
  60     };
  61     std::vector<DevMap> portList;
  62     AddrRangeList defaultRange;
  63     std::vector<DevMap> portSnoopList;
  64
  65     std::vector<int> snoopCallbacks;
  66
  67
  68     /** Function called by the port when the bus is recieving a Timing
  69       transaction.*/
  70     bool recvTiming(Packet *pkt);
  71
  72     /** Function called by the port when the bus is recieving a Atomic
  73       transaction.*/
  74     Tick recvAtomic(Packet *pkt);
  75
  76     /** Function called by the port when the bus is recieving a Functional
  77         transaction.*/
  78     void recvFunctional(Packet *pkt);
  79
  80     /** Timing function called by port when it is once again able to process
  81      * requests. */
  82     void recvRetry(int id);
  83
  84     /** Function called by the port when the bus is recieving a status change.*/
  85     void recvStatusChange(Port::Status status, int id);
  86
  87     /** Find which port connected to this bus (if any) should be given a packet
  88      * with this address.
  89      * @param addr Address to find port for.
  90      * @param id Id of the port this packet was received from (to prevent
  91      *             loops)
  92      * @return pointer to port that the packet should be sent out of.
  93      */
  94     Port *findPort(Addr addr, int id);
  95
  96     /** Find all ports with a matching snoop range, except src port.  Keep in mind
  97      * that the ranges shouldn't overlap or you will get a double snoop to the same
  98      * interface.and the cache will assert out.
  99      * @param addr Address to find snoop prts for.
 100      * @param id Id of the src port of the request to avoid calling snoop on src
 101      * @return vector of IDs to snoop on
 102      */
 103     std::vector<int> findSnoopPorts(Addr addr, int id);
 104
 105     /** Snoop all relevant ports atomicly. */
 106     void atomicSnoop(Packet *pkt);
 107
 108     /** Snoop for NACK and Blocked in phase 1
 109      * @return True if succeds.
 110      */
 111     bool timingSnoopPhase1(Packet *pkt);
 112
 113     /** @todo Don't need to commit all snoops just those that need it
 114      *(register somehow). */
 115     /** Commit all snoops now that we know if any of them would have blocked.
 116      */
 117     void timingSnoopPhase2(Packet *pkt);
 118
 119     /** Process address range request.
 120      * @param resp addresses that we can respond to
 121      * @param snoop addresses that we would like to snoop
 122      * @param id ide of the busport that made the request.
 123      */
 124     void addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id);
 125
 126
 127     /** Declaration of the buses port type, one will be instantiated for each
 128         of the interfaces connecting to the bus. */
 129     class BusPort : public Port
 130     {
 131         /** A pointer to the bus to which this port belongs. */
 132         Bus *bus;
 133
 134         /** A id to keep track of the intercafe ID this port is connected to. */
 135         int id;
 136
 137       public:
 138
 139         /** Constructor for the BusPort.*/
 140         BusPort(const std::string &_name, Bus *_bus, int _id)
 141             : Port(_name), bus(_bus), id(_id)
 142         { }
 143
 144       protected:
 145
 146         /** When reciving a timing request from the peer port (at id),
 147             pass it to the bus. */
 148         virtual bool recvTiming(Packet *pkt)
 149         { pkt->setSrc(id); return bus->recvTiming(pkt); }
 150
 151         /** When reciving a Atomic requestfrom the peer port (at id),
 152             pass it to the bus. */
 153         virtual Tick recvAtomic(Packet *pkt)
 154         { pkt->setSrc(id); return bus->recvAtomic(pkt); }
 155
 156         /** When reciving a Functional requestfrom the peer port (at id),
 157             pass it to the bus. */
 158         virtual void recvFunctional(Packet *pkt)
 159         { pkt->setSrc(id); bus->recvFunctional(pkt); }
 160
 161         /** When reciving a status changefrom the peer port (at id),
 162             pass it to the bus. */
 163         virtual void recvStatusChange(Status status)
 164         { bus->recvStatusChange(status, id); }
 165
 166         /** When reciving a retry from the peer port (at id),
 167             pass it to the bus. */
 168         virtual void recvRetry()
 169         { bus->recvRetry(id); }
 170
 171         // This should return all the 'owned' addresses that are
 172         // downstream from this bus, yes?  That is, the union of all
 173         // the 'owned' address ranges of all the other interfaces on
 174         // this bus...
 175         virtual void getDeviceAddressRanges(AddrRangeList &resp,
 176                                             AddrRangeList &snoop)
 177         { bus->addressRanges(resp, snoop, id); }
 178
 179         // Hack to make translating port work without changes
 180         virtual int deviceBlockSize() { return 32; }
 181
 182     };
 183
 184     /** An array of pointers to the peer port interfaces
 185         connected to this bus.*/
 186     std::vector<Port*> interfaces;
 187
 188     /** An array of pointers to ports that retry should be called on because the
 189      * original send failed for whatever reason.*/
 190     std::list<Port*> retryList;
 191
 192     /** Port that handles requests that don't match any of the interfaces.*/
 193     Port *defaultPort;
 194
 195   public:
 196
 197     /** A function used to return the port associated with this bus object. */
 198     virtual Port *getPort(const std::string &if_name, int idx = -1);
 199
 200     virtual void init();
 201
 202     Bus(const std::string &n, int bus_id)
 203         : MemObject(n), busId(bus_id), defaultPort(NULL)  {}
 204
 205 };
 206
 207 #endif //__MEM_BUS_HH__